Enters the common tendon. Its muscular fibers pass lower than those of the externus, and are inserted into the inner margin of the patella, some into the rectus tendon. Crureus arises from upper two-thirds of the anterior surface of the femur, outer surface of the femur in front of and below the vastus externus, lower half of the external intermuscular septum; fibers end in a superficial aponeurosis which forms the deepest portion of the common terendon. They arise from a series of transverse arches with intervening bare spaces on the front of the femur. Between the crureus and the vastus internus most of the internal surface of the bone is free. The common or suprapatellar tendon is inserted into the forepart of the upper border of the patella, and a few fibers are prolonged over its anterior surface into the ligamentum patellae. A large, thick ligament surrounding the patella and inserted into the tubercle of the tibia. Subcrureus is the name of a few fibers which may be regarded as the deepest layer of the crureus. Origin, anterior surface of the femur in the lower fourth; insertion, separated by a fat layer from the vasti into the synovial membrane of the knee-joint. Hunter's canal is a three-cornered passage in the middle two-fourths of the thigh, in the angle between the adductors magnus and longus and vastus internus. It is made a canal by a bridge of fascia, and contains the femoral artery, vein, and long saphenous nerve. Nerves. — Anterior crural for the quadriceps and sartorius; superior gluteal for the tensor vaginae femoris. Actions. — Satorius flexes the hip and knee with eversion of the thigh; rotates the leg inward. Quadriceps femoris extends the leg; not necessary for the maintenance of the erect attitude. Rectus femoris also flexes the hip; its posterior head is tense when the thigh is bent. Lower fibers of the vastus internus draw the patella in. Tensor vaginae femoris rotates the thigh in and abducts, assisted by the gluteus maximus; counteracts the gluteus maximus, which tends to draw the iliotibial band backward. The posterior femoral region (hamstrings). — Biceps Femoris. — Origin, long head by a tendon common to it and semitendinosus from inner impression on the lower part of the ischial tuberosity, and from the sacrosciatic ligament; short head from the lower two-thirds of the outer lip of linea aspera and external intermuscular septum; fibers from both heads end in a tendon inserted into the upper and outer part of the head of the fibula by two portions embracing the external lateral ligaments. Semitendinosus. — Arises from the tuberosity of the ischium and tendon common to it and biceps for 3 inches. Terminates in the lower third of the thigh in a long, slender tendon, and curves forward in an expanded form to insert on the upper part of the inner surface of the tibia or anterior crest of the tibia, and sends a process to the fascia of the leg. Semimembranosus. — Origin, tuberosities of the ischium above and outside the tendon of the biceps and semitendinosus, and its tendon is grooved posteriorly for the common tendon of those two muscles. Tendon of origin is on the outer side of the muscle for three-fourths the length of the thigh; tendon of insertion, on the opposite side of the muscle, and turns forward and is inserted by four parts: (1) into a horizontal groove on the back of the inner tuberosity of the tibia; (2) expansion is sent up and in as the posterior oblique ligament of the knee-joint; (3) down to the fascia over the popliteus muscle; (4) to form the short internal lateral ligament of the knee-joint. The internal femoral region. — Pectineus. — Origin, iliopectineal line, and slightly from bone in front of this, and from the fascia over the muscle; insertion, femur behind the small trochanter and upper part of the line passing from this trochanter to the linea aspera. Adductor Longus. — Flat and triangular, internal to the pectineus, on same plane. Origin, short tendon from the body of the pubis below the crest and near the angle; insertion, inner lip of the linea aspera, united to the vastus internus in front and adductor magnus behind. Gracilis. — Origin, inner margin of pubic bone and a portion of its inferior ramus; thin and flat, then narrow and thicker. A round tendon in the lower third of the thigh, curving forward below, inserted into the inner side of the tibia just above the semitendinosus, and covered by the sartorius. Adductor Brevis. — Origin, body and inferior ramus of the pubis below the adductor longus, between the gracilis and obturator externus; insertion, into the whole line from the small trochanter to the linea aspera behind the pectineus. It lies between the adductor magnus and longus. Adductor Femoris Minirnus. — This is what is described with the adductor magnus, usually as its anterior and superior portion. Origin, body of the pubis and ischiopubic rami; insertion, femur, in a line from the quadratus femoris to the upper end of the linea aspera, and a short distance along it. Adductor Magnus. — Origin, ischial ramus internal to the above muscle and outer half of the triangular space on the posterior inferior surface of the tuberosities of the ischii; fibers pass in two layers, one to the inner lip of the linea aspera, and the other on the inner side of the opening for the femoral vessels by a distinct rounded tendon to insert on the adductor tubercle on the inner condyle of the femur. The femoral attachment is interrupted by three or four tendinous arches for the perforating arteries. Actions. — All adduct the thigh. Pectineus, adductor longus and brevis flex the hip, while part of adductor magnus from the ischial tuberosity to the condyle may extend the thigh and rotate in. Gracilis flexes the knee and rotates the leg inward. Adductors and opponens, the gluteals, balance the body in walking. (1) Anterior fibers of the gluteus medius (2) and minimus; (3) tensor vaginae femoris; and some say (4) the condylar part of the adductor magnus, rotate the thigh inward. Muscles of the leg The anterior tibiofibular region (extensors). — Tibialis Anticus. — Origin, outer tuberosity of the tibia, upper half of the outer surface of that bone, and adjacent interosseous membrane, fascia of the leg, and intermuscular septum; insertion, oval mark on the inner and lower part of the internal cuneiform and first metatarsal dividing into two slips. Extensor Longus or Proprius Hallucis. — Origin, middle two-fourths of the narrow anterior surface of the fibula and contiguous portion of the interosseous membrane; insertion, base of the terminal phalanx of the great toe on the dorsal aspect. It spreads in an expansion on each side over the metatarsophalangeal articulation, and almost always sends a slip to the base of the first phalanx. Extensor Longus Digitorum Pedis. — Origin, external tuberosity of the tibia, head, and upper two-thirds of the anterior surface of the fibula, very largely from the septa and fascia and interosseous membrane above the origin of the extensor proprius hallucis. Tendon divides into four slips for the outer four toes. They are continued into expansions which are joined on the first phalanx by processes from the interossei and lumbricales. They divide into three parts — the middle inserted into the middle phalanx; the lateral parts unite, and are inserted into the base of the terminal phalanx as in case of the extensors of the fingers. Peroneus Tertius. — Origin, lower third or more of the anterior surface of the fibula, from the interosseous membrane, from the septum between it and the peroneiis brevis; insertion, upper surface of the base of the fifth metatarsal, sometimes the fourth. This muscle is peculiar to man. The fibular or peroneal region. — Peroneus Longus. — Origin, head and upper two-thirds of the external surface of the fibula, fascia of the leg, and septa on each side. Tendon begins in the lower half of the leg, passes behind the external malleolus; then forward on the outer side of the os calcis, winds around the tuberosity of the cuboid, and enters its groove, crosses the sole obliquely, and is inserted into the outer side of the tuberosity of the first metatarsal, and slightly into the internal cuneiform; a frequent offset to the base of the second metatarsal and first dorsal interosseous. Peroneus Brevis. — It lies deeper than the peroneus longus. Origin, lower two-thirds of the external surface of the fibula from the septa and a flat tendon on the surface turned toward the bone; insertion, tuberosity at the base of the fifth metatarsal, sending a small slip to the outer edge of the extensor of the little toe or forepart of the metatarsal bone. The posterior tibiofibular region (flexors). — Superficial muscles. — Gastrocnemius, — Gastrocnemius has two large heads from the femur, terminating at the middle of the leg in a common tendon. Outer head from the depression on the outer side of the external condyle above the tuberosity, and from the posterior surface of the femur just above that condyle. Inner head from the upper part of the internal condyle. The two heads join with the soleus and are inserted into the tendo Achillis. Soleus. — Origin, externally from the posterior surface of the head and upper third of the shaft of the fibula; internally, oblique line and inner border of the tibia to its middle, and from a tendinous arch over the popliteal vessels and nerve; fibers rise to a large extent from two tendinous laminae which descend in the muscle, one from the fibula and one from the tibia. Fibers from the anterior surfaces of these laminae converge to a median septum; fibers from their posterior surfaces pass down and back to an aponeurosis covering the back surface of the muscle. The tendon of insertion is prolonged from this aponeurosis, joined by the median septum. Muscular fibers are continued down on the deep surface of the tendo Achillis near to the heel. The gastrocnemius and soleus form the calf of the leg. Tendo Achillis, broad at first, contracts to within 1/2 inches of the heel, then expands, and is inserted into the middle and lower parts of the posterior surface of the tuberosity of the os calcis, a bursa having all the characters of a synovial membrane, with vascular and fatty synovial tufts, separating it from the upper part of this surface. Plantaris. — Origin, femur above the external condyle and from the posterior ligament of the knee-joint. Muscular belly 3 to 4 inches long, and the long, slender tendon turns in between the gastrocnemius and soleus to the inner border of the tendo Achillis, and inserted by its side into the os calcis. Popliteus. — Origin, round tendon, one inch long, from the groove on the outer surface of the external condyle of the femur, within the capsule of the joint, in contact with the semilunar cartilage, and by muscular fibers from the ligamentum popliteus arcuatum. Fibers pass down and are inserted into the triangular surface of the tibia above the oblique line, and into the aponeurosis over the muscle. The deep muscles (flexors). — Flexor Longus Digitorum Pedis. — Origin, inner portion of the posterior surface of the tibia for the middle two-fourths of its length, from the aponeurosis over the tibialis posticus. Descends behind the internal malleolus of the tibia, passes forward and obliquely outward, having crossed the tibialis posticus tendon in the leg, and now crossing that of the flexor longus hallucis, in each case superficially. It divides into four parts for terminal phalanges of the four lesser toes. Tibialis Posticus, beneath the two long flexors. Origin, posterior surface of the interosseous membrane, outer part of the posterior surface of the tibia below the oblique line of the middle of the bone, whole inner surface of the fibula, and from the aponeurosis over it. Tendon along the inner border of the muscle, free at the level of the lower tibiofibular articulation, passes behind the inner malleolus, inserted into the tuberosity of the scaphoid, with offsets to the three cuneiform, to cuboid, to bases of the second, third, and fourth metatarsals, and to the transverse tarsal ligament and flexor longus hallucis tendon, and sends a thin process back to the sustentaculum tali of the os calcis. Flexor Longus Hallucis. — Origin, lower two-thirds of the posterior surface of the fibula, septum between it and the peronei; aponeurosis common to it and flexor longus digitorum. Tendon at the posterior surface of the muscle traverses groove on the back of the astragalus and under surface of the sustentaculum, gives slip to the flexor longus digitorum in the sole of the foot, and proceeds to the base of the terminal phalanx of the great toe. Muscles of the foot The dorsal region (instep). — Extensor Brevis Digitorum Pedis. — Arises from forepart and upper and outer surface of the os calcis, in front of the groove for the peroneus brevis tendon, and from the anterior ligament of the ankle. The tendon has several vertical leaflets from which muscular fibers arise, dividing into three bellies which unite with the outer border of the long extensors for the second, third, and fourth toes. The plantar region (sole). — The central group. — Flexor Brevis Digitorum and Flexor Accessorius Lumbricales. — Four in number. Origin, at points of division of the flexor longus digitorum tendon, each attached to two tendons, except the most internal one; they pass to the inner side of the four outer toes; inserted into the bases of the first phalanges. The internal group. — Abductor Hallucis, flexor brevis hallucis, and adductor hallucis (oblique transverse portions). The external group. — Abductor Minimi Digiti, and flexor brevis minimi digiti. Actions. — Popliteus flexes the knee and rotates the leg inward, pulls on the capsule of the joint, and keeps the popliteal bursa open. The dorsum of the foot and anterior surface of the leg is the extensor surface; the opposite side is the flexor surface, so that raising the foot toward the front of the leg is really extension, and depressing it is flexion; it is customary to apply reverse terms to these acts. Gastrocnemius flexes the knee, extends the ankle, combines with the soleus, and lifts the heel or raises the body on toes. Tibialis anticus and peroneus tertius flex the ankle; the former rotates inward, adducts, raises the first metatarsal bone. Tibialis posticus, peroneus longus and brevis are extensors of the ankle-joint. Tibialis posticus and flexors of the toes rotate the foot in. The three peronei and extensors of the toes rotate outward. Peroneus longus strengthens the transverse arch, lifts the outer border of the foot in walking, extends the foot, depresses the first metatarsal, abducts the forefoot, rotates outward. Flexors and extensors of the toes, interossei, and lumbricales act as do the corresponding muscles of the hand. Flexor accessorius modifies the action of the flexor longus digitorum, as those tendons cannot enter the foot in a straight line. The extensor brevis digitorum does the same for the extensor communis, though here they are not so much needed, and their function is not so evident. Extensors of the foot slightly rotate inward; flexors of the foot slightly rotate outward; plaiitaris indirectly pulls up the capsule of the ankle-joint and slightly aids the gastrocnemius. Flexors of the foot. Extensors of the foot. Tibialis anticus. Tendo Achillis. Extensor communis digitorum. Peroneus longus and brevis. Extensor proprius hallucis. Tibialis posticus. Peroneus tertius. Flexor longus digitorum and hallucis. Adduction. Abduction. Tibialis posticus (strongly). Peroneus brevis. Tendo Achillis (weakly) . Peroneus longus. Perhaps tendons behind the inner malleolus, perhaps the tibialis anticus. Rotation in. Rotation out. Tibialis anticus (strongly). Peroneus longus. Tendo Achillis. Extensor communis digitorum, Peroneus tertius.
Key Takeaways
- Understanding muscle anatomy and physiology is crucial for recognizing injuries and providing appropriate care in emergency situations.
- Knowledge of specific muscles' origins, insertions, and actions can help in diagnosing and treating musculoskeletal issues.
- The quadriceps and hamstrings play critical roles in knee and hip movement.
Practical Tips
- Learn the key muscle groups involved in walking and running to better understand how to treat injuries or provide support during survival scenarios.
- Identify common muscle attachment points on bones, such as the patella and tibia, for quick assessment of potential injuries.
- Understand that muscles like the quadriceps and hamstrings are essential for maintaining balance and posture.
Warnings & Risks
- Be cautious when applying manual pressure or massage to injured areas; improper technique can exacerbate damage.
- Avoid overexertion in unfamiliar environments, as muscle strains can occur more easily without proper conditioning.
- Always prioritize rest and recovery after physical exertion to prevent further injury.
Modern Application
While the detailed anatomical descriptions from this chapter may seem outdated, the fundamental principles of muscle function and anatomy remain crucial for modern survival preparedness. Understanding how muscles work can help in recognizing injuries, providing first aid, and even in designing more effective physical training regimens to prepare for potential emergencies.
Frequently Asked Questions
Q: What are the primary functions of the quadriceps and hamstrings?
The quadriceps primarily extend the leg at the knee joint, while the hamstrings flex the knee. Both muscle groups are essential for maintaining balance and posture.
Q: How can I identify common muscle attachment points on bones during an emergency?
Common attachment points include the patella (kneecap) for quadriceps muscles, and the tibia (shinbone) for muscles like the gastrocnemius. Knowing these points helps in assessing potential injuries.
Q: What are some practical applications of understanding muscle tissue from this chapter?
Understanding muscle tissue can help in recognizing and treating musculoskeletal injuries, providing appropriate first aid, and even in designing effective physical training programs to prepare for emergencies.